Varicella-zoster virus (VZV) (VZV)

Varicella-zoster virus (VZV), also known as human alphaherpesvirus 3, is a highly contagious DNA virus belonging to the Herpesviridae family. It is the causative agent of two distinct clinical entities: varicella (chickenpox), resulting from primary infection, and herpes zoster (shingles), which occurs upon reactivation of the virus from its latent state in the cranial nerve or dorsal root ganglia. The virus primarily targets epithelial cells and neurons, utilizing complex mechanisms to evade the host immune system and establish lifelong persistence. In a clinical context, VZV is addressed through both preventative and therapeutic strategies. Antiviral medications like acyclovir target the viral DNA polymerase to halt replication during active infections. Conversely, the 'whole live-attenuated virus' (specifically the Oka strain) serves as the active immunogenic component in several vaccines designed to elicit a protective immune response. While highly effective, the use of live-attenuated VZV requires careful screening, as it poses a risk of disseminated infection in immunocompromised patients. Modern vaccine development has also introduced recombinant subunit options to mitigate these safety concerns while maintaining high efficacy in older populations.

Other names

Human alphaherpesvirus 3HHV-3Chickenpox virusHerpes zoster virusLive-attenuated varicella-zoster virus

Antiviral drugs typically inhibit VZV DNA polymerase to prevent viral replication. Vaccines utilize live-attenuated or recombinant viral proteins to induce humoral and cell-mediated immune responses, specifically priming T-cells and B-cells to recognize viral antigens upon future exposure.